In the inventor's co-pending U.S. patent application serial no. 07/086,281 entitled SQUEEZE ROLL AND ACTUATOR ASSEMBLY UTILIZING INFLATABLE BAGS, now patent no. 4,770,095, the inventor sets forth an actuator in which two inflatable bags are mounted at one end on opposite sides of a bar, and the opposite ends of the two bags are interconnected by a yoke utilizing a pair of rods disposed on opposite sides of the bags. The inflatable bags contain a fluid which is pressurized, and the force exerted on a load is derived from the yoke and is a function of the differential pressure of the fluid in the two bags. The present invention is an improvement on the devices of that patent.
It is an object of the present invention to provide an actuator suitable for use with squeeze rolls which is more responsive than actuators previously known. The actuator of the inventor's prior patent, referred to above, is a marked improvement over prior devices, but the present invention provides an actuator which is significantly more responsive to the type of roll deflection which occurs in processing sheet material through a squeeze roll. Such operations require constant pressure on the sheet as it rolls through the rolls, and accordingly, a variation in the sheet must produce a rapid adjustment by the actuator to prevent an excessive change in pressure by the rolls. The actuator of the present invention increases responsiveness over the inventor's prior actuator by reducing the mass of the moving structure of the actuator.
It is also an object of the present invention to reduce the size and cost of the actuator over that of the inventor's prior construction. In addition, the inventor seeks to provide a simpler and less costly positive stop to the actuator and a more reliable construction for pressurizing the inflatable bags.